1. Field of the Invention
The present invention generally relates to a technique and application of an optical element and a light source module, in particular, to a light diffusion device, a backlight module, and a liquid crystal display.
2. Description of Related Art
Liquid crystal displays (LCD), having advantages such as thin thickness, high definition, low power consumption, and no radiation, have gradually become mainstream flat display apparatuses. Generally speaking, a liquid crystal display is constituted of a backlight module and an LCD panel. Since the LCD panel is not a self-emission panel, the backlight module is required to provide a uniform surface light source for the LCD panel to display images.
Generally speaking, in order to enable the backlight module to provide the uniform surface light source, normally, several light diffusers are employed to diffuse a spot or linear light source in the backlight module into the uniform surface light source. Further, in order to avoid greatly reducing the brightness of the surface light source caused by the light diffusers, usually, brightness enhancement films are disposed between the light diffusers to enhance the overall brightness of the surface light source.
However, in the prior art, the light diffusers are surface roughened, added with diffusing particles, or surface roughened with the diffusing particles added so as to achieve the uniform light diffusion of the light source in the backlight module into the surface light source of the LCD panel. However, the concentrated light pattern cannot be formed in the above manners, and thus the brightness of the surface light source provided by the backlight module is insufficient. Thus, an optical film, such as the brightness enhancement film must be added to improve the light output quality, which results in the increase of the fabrication cost of the backlight module.